This application relates to and claims priority to corresponding German Patent Application No. 100 26 541.3, which was filed on May 27, 2000, and which is incorporated by reference herein.
The invention relates to a precision positioning apparatus for positioning a component, especially an optical component, such as a set of lenses or mirror, of the type defined in detail in the preamble of claim 1.
Components, especially optical components, frequently require very precise positioning or alignment because they are interactive with other components or because they are used for taking very accurate measurements. In optics, for example, this applies to sets of lenses or mirrors. Thus, for example, very precise axial and/or vertical adjustment is necessary in mirrors, including especially ellipsoid mirrors, for lighting systems, especially in the deep ultraviolet (DUV) range. Normal threads for mounting and guidance are unsuitable for this, since, because of the play necessarily existing at the flanks of the thread, tilting movements and displacements of a nut result in wobble phenomena in the plane perpendicular to the screwing direction, in other words the bearing surface of the nut.
The Spieth company of 73730 Esslingen offers lock nuts under the name xe2x80x9cSpieth-Stellmutternxe2x80x9d for general mechanical engineering. The lock nuts consist of a guide ring and a clamping ring, the two rings being connected to one another elastically. An axially elastic blade or a division in the guide ring and the clamping ring is formed by two closely adjacent perforations from the inside and the outside of the lock nut. The play at the flanks of the thread is eliminated, in other words freedom from play is achieved, by a bracing applied by screws between the guide ring and the clamping ring.
It has proved to be a disadvantage of the xe2x80x9cSpieth lock nutsxe2x80x9d, however, that they tend to be subject to seizing phenomena when adjusted in the prestressed state, because the clamping in the axial direction takes place over the entire circumference. Adjustment of the pretensioned lock nuts is thus impossible. If the prestress is released again to permit adjustment, the wobble phenomena described above recur. This means that exact adjustment and mounting of components, especially of high-precision optical components, becomes very difficult.
Various tilting apparatuses are known for exact angular setting and/or enact setting and adjustment of the tilt of a component. Thus, for example, a tilting apparatus is known for an ellipsoid mirror in which the mirror is adjusted and fixed by means of three screws. A disadvantage here, however, is that the adjustment of one screw always results in the rotation of the focus around the axis through the bearing points of the other two screws. This means that, as a result, the focus of the mirror migrates out of the optical axis of the following optical elements, as a result of which exact adjustment of the ellipsoid mirror entails a high level of effort.
It is therefore an object of the present invention to provide an apparatus of the type mentioned initially whereby the above mentioned disadvantages of the prior art are eliminated, especially one whereby exact adjustment without the risk of seizing during adjustment in the axial direction is possible and/or whereby migration of the focus or the axis of a component to be tilted is avoided,
With the apparatus according to the invention, precise positioning of a component, especially of an optical component, such as for example a set of lenses or a mirror, can be achieved in both the axial and radial directions.
In a very advantageous embodiment of the invention, provision may be made for the axial adjustment device to possess a spindle onto which an adjusting nut can be screwed, the adjusting nut being composed of a guide ring and a clamping ring and the two rings being connected to one another elastically, the clamping ring being capable of being braced against the guide ring via clamping members to eliminate the lateral play of the adjusting nut, wherein individual clamping jaws are formed by incisions in the clamping ring and can each be braced with the guide ring via the clamping members.
As a result of the incisions in the clamping ring, which advantageously extend in the axial direction or at least approximately in the axial direction, discrete or individual clamping jaws are formed. An adjustment in the prestressed state is thus possible without seizing phenomena, since, as a result of the clamping jaws, which are designed for example as short annular segments, engaging differently in the thread, a scraping effect similar to that obtained with a screw-tap occurs.
When provision is made, in an embodiment of the invention, for three clamping jaws or annular segments to be provided, distributed over the circumference, a statically determined three-point bearing is created. It is thus possible to fix the adjusting or setting nut without significant misadjustment because of the three-point bearing.
The apparatus according to the invention can be produced, in particular, for mounting and adjusting optical components such as, for example, an ellipsoid mirror on large thread diameters with a short overall length.
A very advantageous embodiment of a tilting device can comprise one in which the tilting device possesses an inner tilting part and an outer tilting part, the inner tilting part being connected directly or indirectly to the component to be tilted and being connected externally via torsion joints to the outer tilting part, which in turn is connected via torsion joints to a bearing part.
The tilting device according to the invention results in a cardanic suspension. The torsion joints may be formed here as xe2x80x9cnormalxe2x80x9d joints or, in an advantageous manner, are formed as xe2x80x9csolid state jointsxe2x80x9d, in which, for example, a disk is divided by fine cuts so as to produce two rings, specifically an inner ring and an outer ring, which are connected to one another in each case by thin webs and which, for example, form a cardanic disk by means of reciprocally opposite webs and webs arranged at right angles thereto.
In a very advantageous and non-obvious refinement of the invention, provision may be wade for the torsion joints to be so arranged that, when used or an ellipsoid mirror, the neutral axes of the torsion joints point through the focus of the ellipsoid. In this manner, a simple and axis-independent adjustment is achieved.
In this case the reflector of the ellipsoid is located within the inner ring. The tilting device according to the invention provides the possibility of tilting through the focus of an ellipsoid mirror about two axes.
A further advantage of the tilting device according to the invention resides in the fact that only rough production and assembly tolerances are necessary. In addition, only a small structural space is needed. Furthermore, the installation effort is low.
The claimed invention is specially adapted for mounts of a big inner diameter as described in claim 18.